During the Thatcher era, wealthy British people leaving the National Theatre skirted British homeless people in the cardboard cities of the South Bank subway. Today, wealthy Arabs, Russians and Europeans, leaving the Princess Diana memorial playground, skirt Romanian homeless people in the Marble Arch underpass. Can there be any better proof of the astonishing progress London has made in three decades to become the truly global city it is in 2014?

Illustration by David Foldvari.

Even as a professional comedian of 25 years' standing, I nevertheless find it difficult to know what angle to take on this week's much anticipated mass influx of Romanians. I am filing this column, in English, on the morning of Thursday 2 January, but by the time you read it, on Sunday the 5th, it may already be appearing only in Romanian, in an attempt to court some of the 29 million potential new Observer readers the soft right predict will arrive this week. From a business point of view, should I be pro-Romanian or anti-Romanian? While I won't be down at Luton airport handing out Costa coffees any time soon, I do nonetheless wonder which market should I work.

I am not a political speech writer, and I hate to appear cynical, but when Johnson said most of the Romanians "may" be "charming", I don't think he meant this. I think Johnson was being sarcastic. Johnson chose to make Romania synonymous with Transylvania, a region of Romania comprising, at more than 7 million souls, roughly a third of the country's 20 million-plus population. In doing so, was he deliberately evoking fears of the blood-eating Transylvanian vampires of legend, deeply buried in the European collective subconscious? I believe so. For nothing Johnson does is accidental, even things that look like accidents. His wizard zip-wire prang of 2012 was choreographed by CBeebies' Mr Tumble, to exact specifications laid down by a team of spin doctors, in order to court the slapstick vote.

FW Murnau's silent 1922 vampire classic, Nosferatu, is frequently read as antisemitic, the hook-nosed, rat-fancying Count Orlok obviously a 20s Jewish stereotype, as surely as Johnson's flesh-drinking "Transylvanians" represent the Romanians today. Johnson is mired in the folkloric, I should imagine. His evocation of the unholy dining habits of the Romanians is as deliberate as Enoch Powell's allusions to Virgil, and Powell's "rivers of blood" marks the same attitudinal watershed as Johnson's own dinners of blood.

Dracula must be destroyed. Not even Keith Vaz would argue against this, though he may offer him a gingerbread latte. But it's harder to know what to do with dozens of old people on crutches sleeping on the floor between bin bags full of rags, or crammed by unscrupulous landlords into unregulated low-rent ex-council properties in market towns forgotten by party politics. You can't just creep up and drive stakes through their hearts, even though Johnson's calculatedly casual allusion to the vampire myths seems to be inviting Londoners to do so.

As a commercial traveller, delivering my humour content to customers nationwide, I don't think the service industries of Britain could cope without east European workers, even if they do feast on human blood, take gas form, attract vermin, and poison our wells. From the lowliest Travelodge to the highest Hotel du Vin, every front desk I approach is manned by an eastern European, their literacy and numeracy skills putting them ahead of one third of the British workforce.

The "Off-Liscenese" near my home and the "Babelon Cafe", Nicholson Street, Edinburgh, are just two examples, off the top of my head, of British businesses that have managed to spell their own names two different ways on the front of their own premises. And, while the extract from the lyrics of the Waterboys' Fisherman's Blues, hand-painted on the wall of my room in the Morrison hotel, Dublin, sports a glaring misused possessive apostrophe, it is unlikely that the Bulgarian woman on reception was responsible, as her English was perfect.

We fear what we do not know. And what do I, I wonder, know about the Romanians? Well, like many people, Johnson included, I should imagine, say the word Romania to me, and I think instantly of Stefan Niculescu, Octavian Nemescu and Corneliu Cezar. We all accept that the Romanian electro-acoustic composers of the postwar era were decent, hard-working pioneers in their field. But it is not decent, hard-working Romanian electro-acoustic composers who will be coming here and undercutting decent, hard-working Polish immigrants who have spent 10 years undercutting the decent, hard-working British workers at the hand car wash by the cemetery on the bypass, now closed. And I should be very surprised if British artists applying for grants to drop ring modulators down wells suddenly find there is a bald Romanian with a communist beard trying to gazump their funding bid. The last place in Europe a Romanian would come to pursue a career as a state-funded experimental artist would be Britain.

Of course, it is very easy for me, a middle-class man, economically shielded from any immediate negative impact of surges in immigration, to adopt a moderate attitude to the imminent arrival of 29 million Romanian vampire Gypsies coming to eat our children, but pointing this out won't stop the comments section under this article from going on and on about it. And I need an electrician. No one returns my calls.

Stewart Lee's Much A-Stew About Nothing is currently at the Leicester Square theatre, London, and then touring. See stewartlee.co.uk